Six months after U.S. troops invaded Grenada and ousted a Marxist regime, island officials showed Palm Beach County developer E. Llwyd Ecclestone Jr. a sacked military installation they thought could become a golf course.

Ecclestone, developer of the vast PGA National tennis and golf community near Palm Beach Gardens, also was asked in April 1984 to consider investing in a bank, a radio-television station, a brewery or a marina-boating operation in Grenada.

In all, Ecclestone said, he made four 5 1/2-hour flights aboard his private jet to the island before dropping plans to build a resort and golf complex.

``I had serious money (invested). I wasn`t just playing around,`` he said.

Ecclestone`s interest in the Caribbean island is documented in correspondence that former U.S. Rep. Dan Mica donated to Florida Atlantic University in Boca Raton after he left Congress in January.

Mica, a Democrat from Lake Worth who represented southern Palm Beach and northern Broward counties, sent to FAU the letters he received and the responses he mailed to constituents in the last five years of his tenure in the House.

Ecclestone said last week that he reached an agreement with the provisional government in 1984 to lease 240 acres on Grenada to build a golf course and a 250-room resort hotel with 100 oceanfront villas.

But a major drawback, according to Ecclestone`s letter to the White House, was persuading Congress to release $40 million appropriated for completion of an airport and an electric system, among other projects.

Ecclestone`s letter to the White House`s Office of Private Sector Initiatives said that he had spoken to Mica, and that the congressman said he would try to assist. Ecclestone sent Mica a copy of that letter, accompanied by a short cover letter.

Ecclestone said he flew Arnold Palmer`s golf course architects to the site in Grenada and that he amassed $7,000 in travel costs on each of his four trips.

He dropped the project when the State Department failed to form a consortium for the deal or provide low-interest investment financing, Ecclestone said.

Mica, contacted at his home in Virginia, was disturbed that people who wrote to him in Congress might see their names in print.

He said that would break an agreement he made when he donated the papers that FAU would not make them available for a couple of years and only then for ``scholarly purposes.``

He said he would contact FAU to re-emphasize his wishes, but FAU library director William Miller said he had not heard from Mica.

Miller said he thought it would be all right to let the Sun-Sentinel inspect the documents for a generic story about their arrival, which was published in January.

``I don`t know what to say. He`s always said he wanted them confidential for 20 years. I think that`s a little excessive,`` Miller said.

``My own impulse was to not let a reporter look at it. But on the other hand, why not?`` Miller said.

If Mica calls and insists that the collection be locked away, Millar said he would honor the request.

Mica agreed to provide congressional papers to FAU after he was elected to Congress in 1978.

He was the first FAU graduate elected to Congress, and was the university`s first student government president. He has also been nominated to be the next president of FAU in a search currently under way.

Ecclestone said his trips to Grenada were part of an effort by the Reagan administration to encourage American businessmen to invest in that nation to strengthen its economy.

The government`s Marxist regime was deposed in October 1983 when U.S. Marines and Rangers and a small contingent from other Caribbean nations invaded the island nation and overpowered the militia and so-called Cuban construction workers.

Ecclestone and his family flew to Grenada on his Citation II jet. He said he thought his was the first private plane to land on a runway he had been told was built by the Soviet Union for military purposes.

In his letter to the White House, Ecclestone said he was shown 170 acres overlooking a harbor that ``allegedly had been dredged to a sufficient depth to become a future base for Russian submarines.``

The land had several ``Cuban or Russian military installations, all of which were leveled during the invasion.``

And although the land was barren, Ecclestone said in his letter that he had been told it would make an excellent golf course complex.

Ecclestone said, however, that he concentrated on another piece of property on Grenada.

Ecclestone`s letter was in one of 58 boxes of files FAU organized in acid- free boxes and folders to preserve the Mica collection. Archivist Carol Finerman was paid $1,365 for almost 200 hours of work from the latter part of January through the first week of May, Miller said.

Whether a room will be set aside for Mica`s correspondence depends on how valuable the collection becomes, Miller said.

``The potential scholarly use is for someone who wants to do a study of interaction of a congressman and his constituents,`` he said.